The Abdominal Wall:
An Overlooked Source of Pain
SAUD SULEIMAN, M.D., and DAVID E. JOHNSTON, M.D.
University of New Mexico School of Medicine, Albuquerque, New Mexico
When abdominal pain is chronic and unremitting, with minimal or no relationship to
eating or bowel function but often a relationship to posture (i.e., lying, sitting, stand-
ing), the abdominal wall should be suspected as the source of pain. Frequently, a local-
ized, tender trigger point can be identified, although the pain may radiate over a dif-
fuse area of the abdomen. If tenderness is unchanged or increased when abdominal
muscles are tensed (positive Carnett’s sign), the abdominal wall is the likely origin of
pain. Most commonly, abdominal wall pain is related to cutaneous nerve root irritation
or myofascial irritation. The pain can also result from structural conditions, such as
localized endometriosis or rectus sheath hematoma, or from incisional or other
abdominal wall hernias. If hernia or structural disease is excluded, injection of a local
anesthetic with or without a corticosteroid into the pain trigger point can be diagnos-
tic and therapeutic. (Am Fam Physician 2001;64:431-8.)
he abdominal wall as a true if the pain is not progressive and if
source of pain has received no evidence of visceral disease is present.
little attention, and only a Certain features may point to a pain
few reviews on the topic source in the abdominal wall (Table 2).
have been published in the Unlike pain that originates in the digestive
past decade.1,2 However, physicians who tract, pain from the abdominal wall is not
consider abdominal wall pain in their made better or worse with food and is not
patients often find it. In fact, overlooking altered by bowel movements. Further-
the abdominal wall as a source of pain more, abdominal wall pain is often
can result in a prolonged, expensive, chronic, nagging and nonprogressive. An
frustrating and dangerous evaluation.
Evaluation TABLE 1
In patients with acute or chronic Some Features
abdominal pain, a number of clinical of Intra-abdominal Pain
findings point to disease inside the ab-
domen (Table 1). When such findings are Nausea, vomiting, weight loss
absent, consideration should be given to Diarrhea, constipation or change in bowel
the abdominal wall as the source of pain. habits
In chronic abdominal pain, the ab- Pain not made better or worse by eating or
dominal wall often can be implicated
Jaundice or other liver function test
based on the findings of the history and abnormalities
physical examination. This is especially Bleeding or anemia
Laboratory evidence of inflammation*
Pain that is the same or increased when the abdominal wall is
*—Elevated white blood cell count, sedimen-
tensed generally indicates an origin in the abdominal wall. tation rate or C-reactive protein level.
AUGUST 1, 2001 / VOLUME 64, NUMBER 3 www.aafp.org/afp AMERICAN FAMILY PHYSICIAN 431
trigger point in the right upper quadrant
TABLE 2 (nerve root T7) can refer pain to the angle of
Some Features of Abdominal Wall Pain the scapula. Patients are often so preoccupied
with the large area of pain spread that they do
Pain often constant or fluctuating; less often, episodic not realize the area of tenderness is extremely
Pain intensity possibly related to posture (e.g., lying, sitting, standing) localized and superficial.
Pain not related to meals or bowel function Several studies have demonstrated the value
No findings of an intra-abdominal process (see Table 1) of the physical examination in the diagnosis of
Abdominal tenderness unchanged or increased when abdominal wall is tensed abdominal wall pain. Investigators in one
(positive Carnett’s sign) study3 found that of 120 emergency depart-
Discrete, tender pain trigger point no more than a few centimeters in diameter ment admissions for acute abdominal pain,
Trigger points often found along lateral margins of the rectus abdominis 23 of 24 patients with a positive Carnett’s sign
muscles or at attachments of muscle or fascia had a normal laparotomy. In another study4 of
With stimulation of trigger point, referral of pain or spreading of pain over a 72 patients with obscure, chronic abdominal
pain and a positive Carnett’s sign, two patients
were found to have pain related to spinal
metastases from recurrence of known gyneco-
algorithm for the diagnosis and management logic malignancies; otherwise, when com-
of abdominal wall pain is provided in Figure 1.2 bined with other information from the his-
Tenderness originating from inside the tory and physical examination, a positive
abdominal cavity usually decreases when a Carnett’s sign was found to be a reliable pre-
supine patient tenses the abdominal wall by dictor of abdominal wall pain.
lifting head and shoulders off the examining Investigators in yet another study5 pros-
table. In contrast, pain originating from the pectively evaluated patients with chronic
abdominal wall is unchanged or increased by abdominal pain who met minimal criteria for
this maneuver (positive Carnett’s sign).3-5 abdominal wall pain. Criteria included a pos-
A tender trigger point in the abdominal itive Carnett’s sign or very superficial tender-
wall is frequently no more than 1 or 2 cm in ness combined with pain that was constant or
diameter. However, it is not unusual for the highly localized to an area no larger than a fin-
pain to spread over a wide area or to be gertip. Four patients proved to have visceral
referred. For instance, pressing on a tender disease (esophagitis, bile duct stricture, diver-
ticular disease and visceral neuropathy); these
patients did not respond to the injection of a
local anesthetic. Of the 79 patients in the
The Authors study, 72 (91 percent) experienced at least
SAUD SULEIMAN, M.D., currently has a private practice in gastroenterology in 50 percent pain relief with one injection of
Lewisville, Tex. Dr. Suleiman graduated from Damascus University School of Medicine, local anesthetic, and at least 56 patients
Syria. He completed a residency in internal medicine at Mercy Hospital Medical Cen- (78 percent) had permanent relief with one or
ter, Chicago, and a fellowship in gastroenterology at the University of New Mexico
School of Medicine, Albuquerque. two injections. Thus, when combined with
other clinical criteria, a positive Carnett’s sign
DAVID E. JOHNSTON, M.D., currently is a gastroenterologist at The Everett (Wash.)
Clinic. Previously, he was on the faculty of medicine at Tufts University School of Med- is valuable as a sign of abdominal wall pain.
icine, Boston, and the University of New Mexico School of Medicine. After graduating
from the University of Pittsburgh School of Medicine, Dr. Johnston completed a resi- Identifiable Causes
dency in internal medicine at Brigham and Women’s Hospital, Boston, and a fellow- HERNIAS
ship in gastroenterology at New England Medical Center, also in Boston.
In addition to the familiar inguinal, femoral
Address correspondence to David E. Johnston, M.D., Gastroenterology, The Everett
Clinic, 3901 Hoyt Ave., Everett, WA 98201-4988 (e-mail: djohnston@everettclinic. and umbilical hernias, a number of unusual
com). Reprints are not available from the authors. hernias can occur (Figure 2). Among these are
432 AMERICAN FAMILY PHYSICIAN www.aafp.org/afp VOLUME 64, NUMBER 3 / AUGUST 1, 2001
The rightsholder did not grant rights to reproduce this item in
electronic media. For the missing item, see the original print
versionof this publication.
FIGURE 1. An algorithm for the diagnosis and management of abdominal wall pain.
the epigastric hernia in the upper midline and becomes incarcerated in a hernia, severe pain
the more subtle spigelian hernia of the poste- can occur without bowel obstruction.
rior lateral abdominal wall fascia, at the edge of
the rectus sheath, which occurs in the mid- Illustrative Case
abdomen. Herniation of bowel loops often A 55-year-old woman presented with multi-
causes visceral pain with vomiting and bowel ple episodes of right upper quadrant abdomi-
obstruction. However, when only omentum nal pain over the course of one year. The
Lateral cutaneous Epigastric
branches of hernia
branches of Posterior layer
intercostal nerves . of rectus sheath
Lateral cutaneous . Umbilical hernia
branches of ..
branch of . Spigelian hernia
ILLUSTRATIONS BY TODD BUCK
Inferior epigastric vessels
branch of subcostal nerve
Rectus abdominis muscle (cut)
FIGURE 2. Locations where pain in the abdominal wall might originate. Epigastric hernias occur
along the linea alba. Spegelian hernias occur below the arcuate line where the inferior epigas-
tric vessels traverse the fascia. Nerve roots passing through or around the lateral edge of the rec-
tus sheath are often subject to irritation.
episodes were separated by months during tectomy. An abdominal CT scan was initially
which she felt well. Each episode started read as normal, but review of the scan showed
abruptly, without warning, and without a rela- herniation of omentum through a defect in
tionship to food. Previously, she had under- the abdominal wall near the site of the chole-
gone computed tomographic (CT) scanning cystectomy scar (Figure 3).
of the abdomen, barium radiography and While the patient’s right hip was being
endoscopy of the digestive tract, and endo- manipulated during a physical examination,
scopic retrograde cholangiopancreatography. her pain abruptly disappeared, along with the
The findings of these studies were normal. tender mass. A ventral hernia was diagnosed
The patient was now admitted with acute and surgically repaired.
right upper quadrant pain. A tender, fluctu-
ant 8-cm mass was felt in the right upper DISCUSSION
quadrant, several centimeters inferior to a As in the illustrative case, the area of tender-
subcostal scar from a previous open cholecys- ness in a ventral hernia may lie several cen-
434 AMERICAN FAMILY PHYSICIAN www.aafp.org/afp VOLUME 64, NUMBER 3 / AUGUST 1, 2001
Abdominal Wall Pain
timeters to the side of a visible surgical scar.
The physical examination for a hernia should The physical examination for a hernia should be performed
be performed with the patient both standing with the patient both standing and supine.
and supine. CT scanning is often useful in the
evaluation of possible hernia, especially in
obese patients.6 However, it is important to
focus the radiologist on the abdominal wall if NEUROPATHIES
the findings of the history and physical exam- Herpes zoster can cause pain for days before
ination suggest a problem in this area, because the onset of vesicles. Painful acute neuropathy
it is not unusual for abdominal wall defects to of the mononeuritis multiplex type can cause
be overlooked on CT scans. sudden, persistent abdominal pain in patients
with diabetes or vasculitis. Nerve root irrita-
OTHER LESIONS tion may result from the compression of nerve
Various lesions can cause acute or chronic roots T7 through L1.14 Nerve root compres-
pain in the abdominal wall. Localized tender- sion can occur in or near the rectus sheath or
ness often occurs in surgical scars several can involve the ilioinguinal nerve.15-19
months after surgery because of the forma- Common causes of abdominal wall pain
tion of neuromas. Endometriosis tends to are summarized in Table 3.
recur in surgical scars.7,8 Hematomas of the
abdominal wall or rectus sheath can occur Idiopathic Abdominal Wall Pain
spontaneously or after surgery, trauma or Many patients present with chronic pain
pregnancy.9,10 Desmoid tumors can also cause that is not related to an identifiable mechanical
chronic abdominal pain.11 Athletes have been or physiologic abnormality in the abdominal
found to develop abdominal wall pain related wall. Dealing with this ambiguous situation is
to myofascial tears or idiopathic intra- somewhat similar to dealing with nonspecific
abdominal adhesions.12,13 low back pain, in that the exact structures and
mechanisms responsible for the pain are often
Pain trigger points frequently seem to lie
along the lateral margins of the rectus abdo-
minis muscles (linea semilunaris), where
cutaneous nerve roots pass around the rectus
sheath. It has been proposed that cutaneous
nerve roots can become injured where they
pass through the abdominal wall, perhaps
by the stretching or compression of the nerve
root along its course through the abdominal
In some instances, a tight belt or other
poorly fitted clothing can cause nerve root
irritation, especially in physically unfit per-
sons with protuberant abdomens. Pain also
FIGURE 3. Abdominal computed tomographic can occur in or around the abdominal wall
scan showing a defect in the abdominal wall
where muscles insert on bones or cartilage.
in the right upper quadrant (arrow). In this
patient, omentum had become incarcerated For example, the pain can occur where the
in a ventral hernia inferior to an old cholecys- rectus abdominis muscles insert on the lower
tectomy scar. ribs or where the lower ribs connect through
AUGUST 1, 2001 / VOLUME 64, NUMBER 3 www.aafp.org/afp AMERICAN FAMILY PHYSICIAN 435
Etiology of Abdominal Wall Pain
Etiology Comments Diagnosis
Hernia Protuberance in abdominal wall that Abdominal CT scanning, abdominal
usually decreases in size when patient ultrasonography, herniography
Rectus nerve entrapment Occurs along lateral edge of rectus Injection of local anesthetic
sheath; worsening of pain with tensing
Thoracic lateral cutaneous Occurs spontaneously, after surgery or History and physical examination
nerve entrapment during pregnancy
Ilioquinal and Lower abdominal pain that occurs after History and physical examination
iliohypogastric nerve inguinal hernia repair
Endometriosis Cyclic abdominal pain Laparoscopy
Diabetic radiculopathy Acute, severe truncal pain involving Paraspinal EMG
T6-T12 nerve roots
Abdominal wall tear Occurs mainly in athletes History and physical examination
Abdominal wall Complication of abdominal laparoscopic Abdominal CT scanning, abdominal
hematoma procedures ultrasonography
Spontaneous rectus Presents as tender, usually unilateral mass Abdominal CT scanning, abdominal
sheath hematoma that does not extend beyond midline ultrasonography
Desmoid tumor Dysplastic tumor of connective tissue; Surgical excision
occurs in young patients (females more
often than males)
Herpes zoster Pain and hyperesthesia followed by History and physical examination
vesicles along a dermatome
Spinal nerve irritation Caused by disorders of thoracic spine CT scanning or MRI studies of
Slipping rib syndrome Sharp, stabbing pain in upper abdomen Hooking maneuver to pull lower
caused by luxation of eighth to ribs anteriorly, which reproduces
10th ribs the pain and sometimes a click
Idiopathic Myofascial pain History and physical examination
CT = computed tomography; EMG = electromyography; MRI = magnetic resonance imaging.
cartilage. The xiphoid cartilage is sometimes
a specific focus of pain. Management
Abdominal wall pain can be thought of as PATIENT EDUCATION AND REASSURANCE
one category of myofascial pain. In this situa- Once a tentative diagnosis of abdominal
tion, muscle or fascial strain can lead to a pain wall pain has been made, it is important to
trigger point. The mechanism for the pain may explain the diagnosis to the patient. The
involve the development of an area of hyperal- patient may be worried about the implications
gesia as a result of myofascial stretch injury.20 of the pain. Furthermore, having to undergo a
436 AMERICAN FAMILY PHYSICIAN www.aafp.org/afp VOLUME 64, NUMBER 3 / AUGUST 1, 2001
Abdominal Wall Pain
long series of diagnostic tests may reinforce
the patient’s anxiety. In this setting, pain can A major goal of trigger-point injection is to confirm the
take on a life of its own. abdominal wall as the pain source.
If there is evidence of a benign source of
abdominal wall pain rather than a serious
internal disease, reassurance should be pro-
vided. The physician can demonstrate how corticosteroid. Steroids presumably reduce
gentle palpation of the pain trigger point can inflammation or result in the thinning of con-
reproduce the pain and its radiation over a nective tissue around painful nerve roots.
wide area of the abdomen. The physician Only a few tenths of a milliliter of a 1:1 mix-
should explain that idiopathic abdominal wall ture of 1 or 2 percent lidocaine and triamci-
pain is similar to idiopathic back or shoulder nolone (Aristocort, in a concentration of 40
pain, in that the involved structure cannot be mg per mL) is required (in any case, less than
precisely described and the cause of the pain 1 mL), so less than 20 mg of triamcinolone is
cannot be exactly identified. used. If the correct spot is injected, the pain
should be relieved immediately, but it may
TRIAL OF LOCAL ANESTHETIC return in a few hours when the effects of the
Much has been written about the treatment lidocaine wear off. Triamcinolone may take
of idiopathic myofascial pain.20,21 The trigger effect slowly over a day or two and then pro-
point for abdominal wall pain can be treated vide long-term relief.
with injection of a small volume of local anes- More than one injection may be required,
thetic. Once the patient identifies the trigger given the hit-or-miss nature of this treatment.
point with one finger, the physician “marches” Such injections can be used to treat a tender
his or her fingers around the area to identify trigger point in a surgical scar (a presumed
the center of the tender spot, which is usually neuroma). If reasonable care is taken, the risks
1 to 2 cm in diameter. associated with the injections should be mini-
A tuberculin syringe with a 5/8-inch needle mal. Repeated injections or larger doses of the
is then used to inject a few tenths of a milli- corticosteroid can cause thinning of the fascia
liter of 1 percent lidocaine (Xylocaine) into and result in a hernia. For this reason, depot-
the most tender spot. A longer needle may be type steroids should not be used in the fascia.
needed in an obese patient. The trigger point
is identified when the tip of the needle causes PHENOL
marked tenderness. Permanent pain relief with anesthesia can
The injection of local anesthetic serves as a be achieved with injections of phenol into the
therapeutic trial and may not provide perma- pain trigger point.22 These injections should
nent relief. However, a significant number of be given by an anesthesiologist or a pain treat-
patients experience pain relief after one or ment subspecialist. Referral to a subspecialist
two injections.5 A major goal of trigger-point also may be considered for patients who have
injection is to confirm the abdominal wall as more generalized pain related to irritation of a
the pain source. In addition, this simple thoracic or intercostal nerve root.
maneuver can help persuade a skeptical
patient that the abdominal wall is, indeed, the OTHER TREATMENTS
source of the pain. In addition to injection of medications,
“dry” needling of pain trigger points without
LOCAL ANESTHETIC AND STEROID medication has been used with some suc-
For more permanent relief of pain, it is often cess.23 A trial of acupuncture or other alterna-
useful to inject a mixture of local anesthetic and tive treatment might be considered.
AUGUST 1, 2001 / VOLUME 64, NUMBER 3 www.aafp.org/afp AMERICAN FAMILY PHYSICIAN 437
Abdominal Wall Pain
Myofascial pain in the abdomen and else- 4. Thomson WH, Dawes RF, Carter SS. Abdominal
wall tenderness: a useful sign in chronic abdominal
where has also been treated using various pain. Br J Surg 1991;78:223-5.
combinations of massage, physical therapy 5. Greenbaum DS, Greenbaum RB, Joseph JG, Natale
with stretching, and cooling topical anesthetic JE. Chronic abdominal wall pain. Diagnostic valid-
ity and costs. Dig Dis Sci 1994;39:1935-41.
sprays.20 Warm soaks and other local methods 6. Rose M, Eliakim R, Bar-Ziv Y, Vromen A, Rachmile-
can be useful. witz D. Abdominal wall hernias. The value of com-
puted tomography diagnosis in the obese patient.
J Clin Gastroenterol 1994;19:94-6.
PSYCHOLOGIC DYSFUNCTION AND PAIN
7. Wolf Y, Haddad R, Werbin N, Skornick Y, Kaplan O.
If the distress caused by a patient’s pain Endometriosis in abdominal scars: a diagnostic pit-
fall. Am Surg 1996;62:1042-4.
seems out of proportion to other findings, the 8. Seydel AS, Sickel JZ, Warner ED, Sax HC. Extra-
presence of depression or other psychologic pelvic endometriosis: diagnosis and treatment. Am
dysfunction should be considered. Pain that J Surg 1996;171:239.
9. Edlow JA, Juang P, Margulies S, Burstein J. Rectus
would normally be a minor nuisance can sheath hematoma. Ann Emerg Med 1999;34:671-5.
become the focus of somatization and be 10. Moreno Gallego A, Aguayo JL, Flores B, Soria T,
greatly magnified by depression. Hernandez Q, Ortiz S, et al. Ultrasonography and
computed tomography reduce unnecessary sur-
A tricyclic antidepressant, given in a low gery in abdominal rectus sheath haematoma. Br J
dosage that minimizes sedation and anticholin- Surg 1997;84:1295-7.
ergic side effects, can be helpful in providing 11. Ward SK, Roenigk HH, Gordon KB. Dermatologic
manifestations of gastrointestinal disorders. Gas-
pain relief.24 Selective serotonin reuptake troenterol Clin North Am 1998;27:615-36.
antagonists may be less effective than tricyclic 12. Simonet WT, Saylor HL, Sim L. Abdominal wall
muscle tears in hockey players. Int J Sports Med
antidepressants for the relief of chronic pain. 1995;16:126-8.
13. Lauder TD, Moses FM. Recurrent abdominal pain
Resources and Referrals from abdominal adhesions in an endurance triath-
lete. Med Sci Sports Exerc 1995;27:623-5.
Family physicians should be able to diag- 14. Longstreth GF. Diabetic thoracic polyradiculopathy:
nose and treat many patients with clear-cut, ten patients with abdominal pain. Am J Gastroen-
localized abdominal wall pain. Alternatively, terol 1997;92:502-5.
15. Peleg R, Gohar J, Koretz M, Peleg A. Abdominal
patients can be referred to a pain treatment wall pain in pregnant women caused by thoracic
center or a pain treatment subspecialist. These lateral cutaneous nerve entrapment. Eur J Obstet
resources can be located through organiza- Gynecol Reprod Biol 1997;74:169-71.
16. Hall PN, Lee AP. Rectus nerve entrapment causing
tions such as the American Pain Society (4700 abdominal pain. Br J Surg 1988;75:917.
W. Lake Ave., Glenview, IL 60025; telephone: 17. Hughes GS, Treadwell EL, Miller J. Syndrome of the
rectus abdominis muscle mimicking the acute
847-375-4715; Web site: www.ampainsoc.org) abdomen. Ann Emerg Med 1985;14:694-5.
or the American Academy of Pain Manage- 18. Rutgers MJ. The rectus abdominis syndrome: a case
ment (13947 Mono Way #A, Sonora, CA report. J Neurol 1986;233:180-1.
19. Knockaert DC, D’Heygere FG, Bobbaers HJ. Ilioin-
95370; telephone: 209-533-9744; Web site: guinal nerve entrapment: a little-known cause of
www.aapainmanage.org). iliac fossa pain. Postgrad Med J 1989;65:632-5.
20. Simons DG, Travell JG, Simons LS. Abdominal muscles.
In: Travell & Simons’ Myofascial pain and dysfunction:
The authors indicate that they do not have any con-
the trigger point manual. Vol. 1. Upper half of body.
flicts of interest. Sources of funding: none reported. 2d ed. Baltimore: Williams & Wilkins, 1999:940-70.
21. Ling FW, Slocumb JC. Use of trigger point injec-
REFERENCES tions in chronic pelvic pain. Obstet Gynecol Clin
North Am 1993;20:809-15.
1. Hershfield NB. The abdominal wall. A frequently 22. Mehta M, Ranger I. Persistent abdominal pain. Treat-
overlooked source of abdominal pain. J Clin Gas- ment by nerve block. Anaesthesia 1971;26:330-3.
troenterol 1992;14:199-202. 23. Hong CZ. Lidocaine injection versus dry needling to
2. Gallegos NC, Hobsley M. Abdominal wall pain: an myofascial trigger point. The importance of the
alternative diagnosis. Br J Surg 1990;77:1167-70. local twitch response. Am J Phys Med Rehabil
3. Thomson H, Francis DM. Abdominal-wall tender- 1994;73:256-63.
ness: a useful sign in the acute abdomen. Lancet 24. McQuay HJ, Moore RA. Antidepressants and
1977;2(8047):1053-4. chronic pain. BMJ 1997;314:763-4.
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